Last updated: 24 Sep 2026 | 15 Views |
Not all mosquitoes are the same. Each group breeds in different places, bites at different times and carries different diseases. When a local administration sprays everything the same way, the budget runs out without hitting the target. This guide summarizes well-established basics about four important mosquito groups in Thailand so leaders and public health teams can plan disease control straight away.
(Illustrative scenario) Sunisa has just transferred in as the public health officer of a subdistrict administrative organization in the lower south of Thailand. Her subdistrict packs many landscapes into one area: dense villages along the main road, rice paddies and backyard pig pens, rubber plantations running up to a forested hillside, and a peat swamp and marshes choked with water lettuce and water hyacinth.
At the council's budget meeting, she proposed buying a new thermal fogging machine together with a mosquito control plan divided by area. One council member raised his hand: "A mosquito is a mosquito. Why complicate things with separate plans? Last year we sprayed the whole subdistrict twice." Another added, "My village gets sprayed and there are still lots of mosquitoes. Spraying is pointless."
Sunisa explained that the mosquitoes biting villagers in the daytime are a different group from those biting rubber tappers at three in the morning, and different again from those rising from the marsh at dusk. Spraying the whole subdistrict twice a year at one time of day matched none of them. She asked for time to prepare a briefing, "Four mosquito types we need to know," for the council to read before voting. That briefing is the outline of this article.
| Topic | Aedes | Anopheles | Culex | Mansonia |
|---|---|---|---|---|
| Key diseases | Dengue, chikungunya, Zika | Malaria | Japanese encephalitis (some species), filariasis (some areas) | Some forms of filariasis |
| Biting time | Daytime, peaks morning and late afternoon | Mostly night | Dusk to night | Mostly dusk to night |
| Breeding sites | Clean-water containers in and around homes | Streams and clear pools in and near forest | Foul water, drains, rice fields | Marshes, swamps, ponds with water plants |
| Main measures | 3 Keeps campaign, spraying around patients' homes | Treated nets, case detection and treatment, personal protection | Wastewater management, JE vaccine, dusk spraying | Removing water plants, personal protection, case surveillance |
Note: the table shows general characteristics. Individual species and local populations can behave differently. Refer to local entomological data from the Department of Disease Control and the regional Office of Disease Prevention and Control.
Identification: Aedes mosquitoes have black bodies and legs with white stripes. The key species are the yellow fever mosquito (Aedes aegypti), which lives closely with people in and around homes, and the Asian tiger mosquito (Aedes albopictus), common in orchards, rubber plantations and shady gardens.
Diseases: Aedes transmit dengue, chikungunya and Zika. Dengue begins with several days of high fever, headache and muscle aches; some patients show bleeding spots, and shock can develop as the fever falls, which makes it dangerous especially for children and people with chronic conditions. Chikungunya causes fever and severe joint pain that can linger for weeks. Zika is usually mild in adults but is of particular concern in pregnancy.
Behavior: Aedes bite in the daytime, especially in the morning and late afternoon. They rest in dark, sheltered spots indoors such as under tables, behind cupboards and on hanging clothes. Females lay eggs on container walls just above the waterline, and the eggs can survive drying for long periods, hatching as soon as rain refills the container.
Breeding sites: Water jars, storage tanks, vases, plant saucers, old tires, coconut shells, latex collection cups in rubber plantations, and rubbish that holds rainwater.
Control: The core is source reduction under the Department of Disease Control's "3 Keeps to prevent 3 diseases" campaign: keep homes tidy so mosquitoes cannot rest, keep rubbish from holding water, and keep water containers covered. Add larvicides or larva-eating fish in containers that cannot be covered. When a dengue case occurs, the disease control team sprays adult mosquitoes around the patient's home within a radius of about 100 meters to break transmission, at dawn or in the evening when Aedes are active.
Role of the thermal fogger: Fog penetrates corners, under-house spaces, shrubs and gardens where Aedes rest, which makes it well suited to spraying around patients' homes in villages.
Identification: The Thai name, roughly "chimney-bottom mosquito," comes from its resting posture: the abdomen tilts up at an angle to the surface, while other mosquitoes rest parallel to it. Many species have dark-and-light spotted wings. Thailand has many Anopheles species, but only some are major vectors.
Disease: Malaria, known locally as "shaking fever" or "forest fever," is caused by Plasmodium parasites. Typical symptoms are fever, chills and sweating, which can recur in cycles. Severe forms can be fatal if treatment is delayed. People at risk include those who go into the forest, rubber tappers and farmers at the forest edge, soldiers and officials in border areas, and mobile workers. Thailand aims to eliminate malaria, so finding and treating cases quickly is vital.
Behavior: Most Anopheles feed at night. Some bite outdoors from early evening, others late at night or before dawn, so behavior varies by species and area. Larvae prefer fairly clean water: slow streams, forest pools and shaded stream banks.
Control: The main measures are rapid case detection and treatment, sleeping under nets (especially insecticide-treated nets), indoor residual spraying in high-risk areas under disease control plans, and repellent use in the forest. Thermal fogging is a supplementary measure in specific situations, such as around villages or worker camps with cases, in the early evening when mosquitoes become active. Follow the advice of the regional disease control office and local vector-borne disease units.
Role of the thermal fogger: Forest edges and rubber plantations have dense vegetation. Fog penetrates resting sites in foliage better than sprays whose droplets settle quickly, so it supports targeted control.
Identification: Culex mosquitoes are dull brown without striking markings. They are the mosquitoes town residents know best, flying indoors at night and whining by the ear. The common urban species breeds in foul water, drains and wastewater ponds, while another group breeds in rice fields and ground pools.
Diseases: Most Culex are a nuisance, but certain rice-field Culex species are major vectors of Japanese encephalitis (JE), with pigs and some birds as reservoir hosts. Most infections cause no or mild symptoms, but cases with brain involvement can be severe and leave lasting disability. Thailand includes JE vaccine in its childhood immunization program. Some Culex species can also transmit certain forms of filariasis in some areas.
Behavior: Culex feed from dusk into the night, enter homes easily, and some fly far from breeding sites. Females usually lay eggs in floating rafts.
Control: Clear drains so water does not stagnate, manage household and livestock wastewater, keep treatment pond edges free of weeds, use suitable larvicides where water cannot be removed, make sure children receive JE vaccine on schedule, and use window screens and bed nets. Spraying should be done in early evening when Culex become active.
Role of the thermal fogger: Fog reaches deep into drains, ditches and ditch-side shrubs, the main Culex resting sites in communities.
Identification: In Thai entomology, "tiger mosquito" usually refers to the genus Mansonia, whose wings and legs carry speckled scales. Some villagers use the same name for other patterned mosquitoes, so identification should be confirmed by an entomology officer.
What makes it different: Mansonia larvae do not come up to the surface to breathe. Instead, they pierce the roots and stems of water plants such as water lettuce and water hyacinth with their breathing tube to draw air. Because they stay under water, larvicides that act at the surface have limited effect.
Disease: Mansonia are important vectors of some forms of lymphatic filariasis, particularly in swamps and marshes in southern Thailand. Filariasis is caused by parasitic worms living in the lymphatic system. Most infected people have no early symptoms, but over years some develop permanent swelling of the limbs. Thailand's long-running elimination work has greatly reduced cases, but surveillance continues in risk and border areas.
Behavior: Mostly active from dusk into the night and aggressive biters; some bite in shade during the day. They are abundant near water with dense aquatic vegetation.
Control: The key measure is removing water plants that shelter larvae in water bodies near villages, which can be combined with a local government's waterway improvement work. Add bed nets, personal protection outdoors at night, and cooperation with any blood surveys or drug distribution programs run by health authorities. Thermal fogging is a supplementary measure in villages next to water, in the evening when mosquitoes are active, and must never be directed onto the water surface.
When a local administration faces several mosquito groups in varied terrain, the right tool must be portable, reach resting sites thoroughly, and handle different chemical formulations as recommended by health authorities. The AIROFOG AT35 thermal fogging machine fits this brief well.
| Feature | Detail | Benefit for the four types |
|---|---|---|
| Type | Thermal fogger | Fog penetrates shrubs, drains, under houses, forest edges |
| Material | 100% stainless steel | Withstands heat, humidity, rain and field use |
| Weight | Lightweight | Easy to carry into plantations, lanes and marsh-side villages |
| Chemicals | Water-based and oil-based | Choose the formulation to suit the site and official advice |
| Certification | Certified in Germany and the UK | Supports quality assessment in procurement |
| Applications | Homes, factories, hospitals, public areas | Villages, child centers, temples, markets, government buildings |
The AT35 is a mosquito fogger a local government can use in many situations: spraying around dengue patients' homes, fogging community drains for Culex, supplementary spraying around forest-edge villages on disease control advice, evening work in marsh-side villages, and general insect control in public areas with the appropriate product. World Health Disinfection Co., Ltd. holds ISO and GMP, checks 100% of units before delivery, provides technicians, spare parts and full after-sales service, and its products meet Thai government equipment standards.
Remember: A thermal fogger reduces adult mosquitoes in the short term. It does not treat disease and cannot replace source reduction, bed nets, vaccination or case detection.
| Target | Best spray time | Where | Parallel measures |
|---|---|---|---|
| Aedes | Dawn or evening | Indoors, under houses, gardens; about 100 m around patients' homes | 3 Keeps, larval surveys |
| Anopheles | Early evening, per disease control advice | Around forest-edge villages, worker camps | Treated nets, case finding and treatment |
| Culex | Early evening | Drains, ditches, ditch-side shrubs | Drain cleaning, wastewater management, JE vaccine |
| Mansonia | Early evening | Marsh-side villages, never onto water | Water plant removal, bed nets |
This is a general example. Adapt it to local data, the disease situation and advice from the district health office or regional disease control office.
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These are general tips. Always check current procurement regulations and your agency's standard equipment price list.
(A composite example based on common local public health experience, not a statement by a real person.)
"Once we color-coded the subdistrict map into Aedes villages, marsh-side villages and forest-edge areas, everything became clearer. Dawn rounds focus on dengue patients' homes; early-evening rounds go to marsh-side villages and community drains. A fogger that is light and does not rust keeps our volunteers motivated. The council member who used to ask why we bothered now asks us to spray his village on schedule."
Q: How can I recognize an Anopheles mosquito?
A: Look at its resting posture: Anopheles usually tilt the abdomen up at an angle, while other mosquitoes rest parallel to the surface. Confirmation should come from an entomology officer.
Q: Does thermal fogging prevent dengue by itself?
A: Fogging cuts adult Aedes that may carry the virus for a short time. It must be combined with source reduction under the 3 Keeps campaign for lasting results.
Q: What time should we spray?
A: It depends on the target. For Aedes, dawn or evening; for night biters, early evening. Avoid rain and strong wind.
Q: Can larvicide control Mansonia?
A: Mansonia larvae cling to plant roots under water, so surface-acting larvicides have limited effect. Removing water plants near villages usually works better. Ask the local disease control unit.
Q: How is Japanese encephalitis prevented?
A: Vaccinate children under the national immunization program, reduce evening bites, and manage Culex breeding sites near homes and animal pens.
Q: Thermal fogger or ULV cold fogger?
A: Thermal fog suits vegetation, drains and enclosed nooks; a ULV cold fogger suits indoor work or places where visible smoke is unwanted. Many local governments keep both.
Q: Which chemicals can the AT35 use?
A: Both water-based and oil-based formulations. Use products registered for public health use at label rates.
Talk to the WHD team about a thermal fogging machine for local governments facing several mosquito types in one area.
See AIROFOG AT35 products and prices, click here
Tel 065-556-6294 | LINE @whd268
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